ASTM D6936 Standard Test Method for Determining Demulsibility of Emulsified Asphalt

The scope includes:

• Material Type: Anionic and cationic emulsified asphalt.
• Emulsion Classification: Rapid-setting (RS) and medium-setting (MS).
• Property Measured: Demulsibility or amount of asphalt broken from the emulsion.
• Test Principle: Chemical breaking of the asphalt emulsion.
• Measurement: Mass of asphalt residue produced after breaking.
• Reporting System: SI units are the standard units.
• Application: Classification, quality control, and performance evaluation of emulsified asphalt.

What is Demulsibility?

Demulsibility describes an emulsified asphalt’s ability to break when exposed to a specified chemical reagent. During the test, the reagent destabilizes the asphalt emulsion and causes asphalt particles to separate from the water phase.

The demulsibility percentage is calculated from the mass of asphalt residue produced during the test compared with the residue present in the original emulsion.

What are the Uses and Benefits of ASTM D6936 Testing?

ASTM D6936 provides controlled information about how emulsified asphalt responds to chemical breaking. Consequently, the test supports classification and quality-control activities.

Key uses and benefits include:

• Quality control: Monitors the breaking behavior of asphalt emulsions.
• Material classification: Helps identify RS and MS emulsified asphalt behavior.
• Product evaluation: Compares different emulsified asphalt formulations.
• Process control: Helps monitor consistency during emulsion production.
• Construction support: Provides information about expected breaking behavior.
• Material development: Supports optimization of asphalt-emulsion formulations.
• Specification compliance: Provides test data for applicable material requirements.

What Problem Does ASTM D6936 Solve?

Emulsified asphalt must break at an appropriate rate during application. If its chemical breaking behavior isn’t properly characterized, manufacturers and engineers may have limited information to evaluate the material.

ASTM D6936 provides a controlled method for measuring how much asphalt breaks when a specified chemical reagent is added. The resulting demulsibility value can then be used for material classification, quality control, and comparison of emulsified asphalt products.

How is the Demulsibility Data Recorded?

The dried asphalt residue is determined by subtracting the tare mass of the container, stirring rod, and wire cloth from the final constant mass.

The demulsibility value is then calculated using the mass of demulsibility residue and the mass of residue present in 100 g of the original emulsified asphalt.

The result is expressed as a percentage by mass.

What Calibration is Required for ASTM D6936?

ASTM D6936 calibration requires a verified balance for accurate mass measurements and a calibrated buret for reliable reagent-volume delivery. The drying oven must maintain 163 ± 3 °C, and reagent concentrations must be prepared and maintained per method requirements. Standardize calcium chloride solutions using procedures such as ASTM D511, and prepare and store the 0.80% dioctyl sodium sulfosuccinate solution according to applicable requirements. Proper maintenance and calibration of this equipment ensure accurate demulsibility testing and reliable data.

ASTM D6936 Testing Technique and Data Collection Guide

A technician conditions and stirs the emulsified asphalt, then places a 100 ± 0.1 g portion into a weighed metal assembly. Calcium chloride or dioctyl sodium sulfosuccinate solution is added gradually while stirring and kneading, breaking the emulsion and separating the asphalt residue. The mixture is transferred to wire cloth, washed with distilled water, and the residue is dried at 163 ± 3 °C, cooled, and weighed to constant mass. The final residue mass, combined with the original emulsion residue value, is used to calculate the demulsibility percentage.

Common Challenges and Troubleshooting in ASTM D6936

Accurate ASTM D6936 demulsibility measurements require stable specimen preparation, controlled temperature, clean contact surfaces, and proper calibration, since small errors significantly affect gram- or milligram-level results. Common challenges include sample contamination, improper specimen preparation, incomplete calibration, thermal gradients, instrument instability, incorrect mixing rates, poor atmosphere control, and contaminated glassware. Each can alter demulsibility behavior or analytical response, leading to inaccurate data.

Important interpretation points include:

• This test method measures the percentage of asphalt residue separated per unit mass of emulsion under specified conditions.
• High values mean the material has high demulsibility; therefore, it may break rapidly in the field.
• Low values highlight potential emulsion stability and indicate that the material may resist breaking.
• The laboratory reports demulsibility in the applicable units.
• The test report includes demulsibility values, sample preparation details, and instrument conditions.

FAQs

1. What does ASTM D6936 measure?

ASTM D6936 determines the demulsibility of emulsified asphalt by measuring the amount of asphalt chemically broken from the emulsion.

2. What types of emulsified asphalt can be tested?

The method applies to anionic and cationic emulsified asphalts of the rapid-setting (RS) and medium-setting (MS) types.

3. What reagents are used in ASTM D6936?

Calcium chloride solutions are used for anionic emulsified asphalt. A 0.80 % dioctyl sodium sulfosuccinate solution is used for the applicable cationic rapid-setting emulsified asphalt test.

4. What equipment is required for ASTM D6936?

The main equipment includes a 1.40-mm wire cloth, metal container, metal stirring rod, 50-mL buret, balance, and drying oven capable of maintaining 163 ± 3 °C.

5. How is ASTM D6936 demulsibility calculated?

Demulsibility is calculated by dividing the mass of demulsibility residue by the mass of residue contained in 100 g of emulsified asphalt and multiplying by 100.

Demulsibility (%) = (A / B) × 100

Link to ASTM D6936 Standard